JP5352602B2 - Brake device for vehicle - Google Patents

Abstract

A brake device for a vehicle is provided in which when there is an abnormality in which a slave cylinder (42) becomes incapable of being actuated, a wheel cylinder (26, 27, 30, 31) is actuated by means of a brake fluid pressure generated by a master cylinder (11), which is actuated by a brake pedal (12). Since idling detection means detects idling of a motor (44) when the rotational speed of the motor (44) is greater than a reference value that is set according to the stroke of the slave cylinder (42), it is possible to reliably and rapidly detect idling of the motor (44). When the idling of the motor (44) is detected, since control means opens a master cut valve (32, 33) and the wheel cylinder (26, 27, 30, 31) is actuated by means of the brake fluid pressure generated by the master cylinder (11), the slave cylinder (42), which has become incapable of being actuated, can be backed up rapidly by the master cylinder (11).

Description

  The present invention converts a brake pedal operation amount by a driver into an electric signal to operate a slave cylinder, and operates a wheel cylinder with a brake hydraulic pressure generated by the slave cylinder, so-called BBW (brake-by-wire). The present invention relates to a type brake device.

  In such a BBW brake device, a slave cylinder that generates brake fluid pressure by operating with an electric signal corresponding to an operation amount of a brake pedal, a cylinder, a piston that is slidably fitted to the cylinder, a motor, and a motor Japanese Patent Application Laid-Open No. 2004-151867 discloses a structure constituted by a speed reducing mechanism that decelerates the rotation of the shaft and converts it into a reciprocating motion of a piston.

JP 2005-343366 A

  By the way, if the motor falls off from the housing of the slave cylinder, the gear of the speed reduction mechanism is damaged, or the meshing failure occurs, the slave cylinder generates brake fluid pressure even though the motor rotates. It may not be possible. In such a case, since the motor rotates, the control device cannot determine the abnormal state, and the switching from the braking by the brake fluid pressure generated by the slave cylinder to the braking by the brake fluid pressure generated by the master cylinder is delayed. May give a sense of incongruity.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to enable quick backup by brake fluid pressure generated by a master cylinder when a motor of a slave cylinder idles.

In order to achieve the above object, according to the invention described in claim 1, a master cylinder that generates a brake fluid pressure by operating a brake pedal, a stroke simulator that applies a reaction force to the operation of the brake pedal, A wheel cylinder that brakes a wheel, a master cut valve that can cut off a liquid path that connects the master cylinder and the wheel cylinder, and a brake cylinder that is disposed between the master cut valve and the wheel cylinder according to the operation of the brake pedal. comprising a slave cylinder that generates brake fluid pressure, and a control device for activating the slave cylinder closed the master cut valve in a state which enables operation of the stroke simulator when the brake pedal is operated, The slave cylinder includes a cylinder body and its First and second pistons that are slidably fitted in the body and are spring-biased in the return direction, respectively, and a first that is adjacent to the front surface of the first piston and communicates with the wheel cylinder of the first system. A hydraulic chamber; a second hydraulic chamber adjacent to the front surface of the second piston and communicating with the wheel cylinder of the second system; and a motor that drives the first and second pistons forward during rotation. An idling detection device for detecting idling of the motor of the slave cylinder, wherein the motor is rotated to change the stroke of the slave cylinder in response to an operation of depressing the brake pedal. further comprising means, said idle detecting means, if the stroke of the slave cylinder in a braking process, wherein the first, one of the second fluid pressure chamber can not generate a brake fluid pressure When also the other is equal to or greater than a predetermined stroke capable of generating brake fluid pressure, so as to perform air-Utateken unloading of the motor, said control means, when the idling of the motor is detected, the master cut valve A vehicle brake device is proposed in which the wheel cylinder is operated with a brake fluid pressure generated by the master cylinder by opening the valve.

  According to the second aspect of the present invention, in addition to the configuration of the first aspect, the idling detection means is configured such that the rotational speed of the motor is larger than a reference value set according to the stroke of the slave cylinder. A vehicular brake device is sometimes proposed which detects idling of the motor.

  According to a third aspect of the invention, in addition to the configuration of the first aspect, the idling detection means detects idling of the motor by comparing the command voltage value of the motor with a torque current value. A vehicle brake device is proposed.

  According to the invention described in claim 4, in addition to the configuration of claim 1, an auxiliary braking means for braking the wheel in place of the slave cylinder until the master cut valve is opened is provided. A vehicle brake device is proposed.

  The first and second master cut valves 32 and 33 of the embodiment correspond to the master cut valve of the present invention, and the electronic control unit U of the embodiment corresponds to the control means of the present invention. The drive motor corresponds to the auxiliary braking means of the present invention.

  According to the configuration of claim 1, in a normal state, the master cut valve is closed and the fluid path connecting the master cylinder and the slave cylinder is shut off, and the slave cylinder is operated according to the amount of operation of the brake pedal by the driver. Is driven, the wheel cylinder is operated by the brake hydraulic pressure generated by the slave cylinder, and a reaction force is applied to the operation of the brake pedal by the stroke simulator. In the event of an abnormal situation in which the slave cylinder becomes inoperable, the wheel cylinder operates with the brake fluid pressure generated by the master cylinder operated by the brake pedal. When the idling detection means detects idling of the motor of the slave cylinder, the control means opens the master cut valve and operates the wheel cylinder with the brake fluid pressure generated by the master cylinder. Back up quickly with a cylinder.

However, in this case, if one of the first and second systems from the first and second hydraulic chambers of the slave cylinder to the plurality of wheel cylinders fails to leak, the first and second hydraulic chambers fail. There is a possibility that it will not be possible to discriminate between idling of the motor and leakage failure, because the load on the motor is hardly generated until the volume of the closed side disappears and the normal side generates brake fluid pressure. Since the idling of the motor is detected when the stroke of the cylinder exceeds a predetermined stroke at which the brake fluid pressure is generated in the hydraulic chamber on the normal side, the leakage failure of the slave cylinder and the motor It is possible to reliably determine idling.

  According to the second aspect of the present invention, the idling detection means detects the idling of the motor when the rotation speed of the motor is larger than the reference value set according to the stroke of the slave cylinder. And it can detect promptly.

  According to the third aspect of the present invention, the idling detection means compares the instruction voltage value of the motor with the torque current value, and the idling of the motor can be detected reliably and promptly.

  According to the fourth aspect of the present invention, since the auxiliary braking means brakes the wheel instead of the slave cylinder until the master cut valve is opened, it is accompanied by switching from braking by the slave cylinder to braking by the master cylinder. The amount of decrease in deceleration can be minimized.

The hydraulic circuit diagram of the brake device for vehicles. (First embodiment) The figure which shows the structure of the control system of the brake device for vehicles. (First embodiment) The hydraulic circuit diagram at the time of the normal braking of the brake device for vehicles. (First embodiment) The hydraulic circuit diagram at the time of abnormality of the brake device for vehicles. (First embodiment) The block diagram of the control system of a slave cylinder. (First embodiment) Explanatory drawing of the calculation method of a pedal stroke-target hydraulic pressure map. (First embodiment) The figure which shows the map which determines idling of a motor. (First embodiment) The figure which shows the map which determines idling of a motor. (Second Embodiment)

  Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.

  As shown in FIG. 1, a tandem master cylinder 11 includes a first piston 14 connected to a brake pedal 12 operated by a driver via a push rod 13, and a second piston 15 disposed in front of the first piston 14. A first fluid pressure chamber 17 in which a return spring 16 is accommodated between the first piston 14 and the second piston 15, and a second fluid in which a return spring 18 is accommodated in front of the second piston 15. A pressure chamber 19 is defined. The first hydraulic pressure chamber 17 and the second hydraulic pressure chamber 19 that can communicate with the reservoir 20 include a first output port 21 and a second output port 22, respectively. The first output port 21 has the fluid paths Pa, Pb, VSA. (Vehicle Stability Assist) Connected to, for example, the wheel cylinders 26 and 27 (first system) of the left and right rear wheel disc brake devices 24 and 25 via the device 23 and the liquid passages Pc and Pd, The two output ports 22 are connected to the wheel cylinders 30, 31 (second system) of the disc brake devices 28, 29 on the left and right front wheels, for example, via the fluid paths Qa, Qb, the VSA device 23 and the fluid paths Qc, Qd. .

  In the present specification, the upstream side of the fluid paths Pa to Pd and the fluid paths Qa to Qd means the master cylinder 11 side, and the downstream side means the wheel cylinders 26, 27; 30, 31 side. To do.

  A first master cut valve 32 that is a normally open solenoid valve is disposed between the liquid paths Pa and Pb, and a second master cut valve 33 that is a normally open solenoid valve is disposed between the liquid paths Qa and Qb. The supply side liquid paths Ra and Rb branched from the liquid path Qa on the upstream side of the second master cut valve 33 are connected to a stroke simulator 35 via a simulator valve 34 which is a normally closed electromagnetic valve. The stroke simulator 35 is a cylinder 36 in which a piston 38 urged by a spring 37 is slidably fitted, and a hydraulic chamber 39 formed on the side opposite to the spring 37 of the piston 38 has a supply side liquid path Rb. Communicate with.

  A tandem slave cylinder 42 is connected to the liquid passage Pb and the liquid passage Qb on the downstream side of the first and second master cut valves 32 and 33. The actuator 43 that operates the slave cylinder 42 transmits the rotation of the motor 44 to the ball screw mechanism 46 via the gear train 45. The cylinder body 47 of the slave cylinder 42 is slidably fitted with a first piston 48A driven by a ball screw mechanism 46 and a second piston 48B positioned in front of the first piston 48A. A first hydraulic pressure chamber 50A in which a return spring 49A is accommodated is defined between the second pistons 48B, and a second hydraulic pressure chamber 50B in which a return spring 49B is accommodated is defined in front of the second piston 48B. When the first and second pistons 48A and 48B are driven in the forward direction by the ball screw mechanism 46 of the actuator 43, the brake hydraulic pressure generated in the first and second hydraulic pressure chambers 50A and 50B is changed to the first and second output ports 51A. , 51B to the liquid paths Pb, Qb.

  The reservoir 69 of the slave cylinder 42 and the reservoir 20 of the master cylinder 11 are connected by a discharge side liquid passage Rc, and the back chamber 70 of the piston 38 of the stroke simulator 35 is connected to the discharge side liquid passage Rc via the discharge side liquid passage Rd. It is connected to the middle part.

  The structure of the VSA device 23 is well known. The first brake actuator 23A controls the first system of the left and right rear wheel disc brake devices 24, 25, and the second system of the left and right front wheel disc brake devices 28, 29. The second brake actuator 23B that controls the same is provided with the same structure.

  As a representative example, the first brake actuator 23A of the first system of the left and right rear wheel disc brake devices 24, 25 will be described below.

  The first brake actuator 23A includes a fluid path Pb that communicates with the first master cut valve 32 located on the upstream side, and fluid paths Pc and Pd that communicate with the left and right rear wheel wheel cylinders 26 and 27 located on the downstream side, respectively. Arranged between.

  The first brake actuator 23A is provided with a common fluid path 52 and a fluid path 53 for the left and right rear wheel cylinders 26, 27, and is always of variable opening disposed between the fluid path Pb and the fluid path 52. A regulator valve 54 composed of an open solenoid valve, a check valve 55 arranged in parallel to the regulator valve 54 to allow the brake fluid to flow from the liquid path Pb side to the liquid path 52 side, the liquid path 52 and An in-valve 56 composed of a normally-open electromagnetic valve disposed between the fluid paths Pd and a check valve that is disposed in parallel to the in-valve 56 and allows the brake fluid to flow from the fluid path Pd side to the fluid path 52 side. 57, an in-valve 58 formed of a normally-open electromagnetic valve disposed between the liquid path 52 and the liquid path Pc, and a liquid path from the liquid path Pc side disposed in parallel to the in-valve 58. A check valve 59 that allows the brake fluid to flow to the second side, an out valve 60 that is a normally closed electromagnetic valve disposed between the fluid path Pd and the fluid path 53, and is disposed between the fluid path Pc and the fluid path 53. Brake fluid from the liquid path 53 side to the liquid path Pb side disposed between the liquid path 53 and the liquid path Pb, and the out valve 61 composed of the normally closed solenoid valve, the reservoir 62 connected to the liquid path 53, and the liquid path Pb. A check valve 63 that allows the flow of oil, a pump 64 that is disposed between the liquid passage 52 and the liquid passage 53 and supplies brake fluid from the liquid passage 53 side to the liquid passage 52 side, and a motor 65 that drives the pump 64. A pair of check valves 66 and 67 provided on the suction side and the discharge side of the pump 64 to prevent the backflow of the brake fluid, and between the check valve 63 and the intermediate position of the pump 64 and the liquid passage Pb. And a suction valve 68 of the closed electromagnetic valve.

  The motor 65 is shared by the pumps 64 and 64 of the first and second brake actuators 23A and 23B. However, dedicated motors 65 and 65 are provided for the pumps 64 and 64, respectively. Is also possible.

  As shown in FIG. 1 and FIG. 2, a first fluid pressure sensor Sa that detects the fluid pressure is connected to the fluid path Pa upstream of the first master cut valve 32, and downstream of the second master cut valve 33. A second fluid pressure sensor Sb that detects the fluid pressure is connected to the fluid channel Qb, and a third fluid pressure sensor Sc that detects the fluid pressure is connected to the fluid channel Pb downstream of the first master cut valve 32. Connected. As the third hydraulic pressure sensor Sc, the hydraulic pressure sensor for controlling the VSA device 23 is used as it is.

  The electronic control unit U connected to the first and second master cut valves 32 and 33, the simulator valve 34, the slave cylinder 42 and the VSA device 23 includes the first hydraulic pressure sensor Sa and the second hydraulic pressure sensor Sb. The third hydraulic pressure sensor Sc, the brake pedal stroke sensor Sd for detecting the stroke of the brake pedal 12, the slave cylinder stroke sensor Se for detecting the stroke of the slave cylinder 42, and the motor for detecting the rotation angle of the motor 44. The rotation angle sensor Sf is connected to wheel speed sensors Sg that detect the wheel speed of each wheel.

  In the electronic control unit U, the motor 44 is in an idling state, that is, the motor 44 is dropped from the slave cylinder 42, the gear train 45 of the actuator 43 or the ball screw mechanism 46 is damaged, and the motor 44 is unloaded or low. An idling detection means M1 is provided to detect a state of rotating with a load.

  Next, the operation of the embodiment of the present invention having the above configuration will be described.

  First, a normal braking action at normal time will be described based on FIG.

  When the system normally functions, when the first hydraulic pressure sensor Sa provided in the fluid path Pa detects that the driver depresses the brake pedal 12, the first and second master cut valves 32 made up of normally open solenoid valves. 33 are excited to close, and the simulator valve 34 formed of a normally closed electromagnetic valve is excited to open. At the same time, the actuator 43 of the slave cylinder 42 is actuated to advance the first and second pistons 48A and 48B, whereby brake fluid pressure is generated in the first and second fluid pressure chambers 50A and 50B. Is transmitted from the first and second output ports 51A, 51B to the liquid passage Pb and the liquid passage Qb, and the disc brake is opened from both the liquid passages Pb, Qb via the in-valves 56, 56; It is transmitted to the wheel cylinders 26, 27; 30, 31 of the devices 24, 25; 28, 29 to brake each wheel.

  Further, since the simulator valve 34 composed of a normally closed solenoid valve is excited and opened, the brake simulator 35 that has generated the second hydraulic pressure chamber 19 of the master cylinder 11 opens the simulator valve 34 through the opened simulator valve 34. By transmitting the piston 38 against the spring 37 while being transmitted to the hydraulic chamber 39, the stroke of the brake pedal 12 is allowed and a pseudo pedal reaction force is generated to eliminate the driver's uncomfortable feeling. Can do.

  And the brake hydraulic pressure by the slave cylinder 42 detected by the second hydraulic pressure sensor Sb provided in the fluid path Qb corresponds to the brake hydraulic pressure by the master cylinder 11 detected by the first hydraulic pressure sensor Sa provided in the fluid path Pa. By controlling the operation of the actuator 43 of the slave cylinder 42 so as to be large, the braking force corresponding to the operation amount input to the brake pedal 12 by the driver is generated in the disc brake devices 24, 25; Can be made.

  Next, the operation of the VSA device 23 will be described.

  When the VSA device 23 is not operating, the regulator valves 54 and 54 are demagnetized and opened, the suction valves 68 and 68 are demagnetized and closed, and the in-valves 56 and 56; 58 and 58 are demagnetized and opened. The out valves 60, 60; 61, 61 are demagnetized and closed. Therefore, when the driver depresses the brake pedal 12 to perform braking and the slave cylinder 42 operates, the brake hydraulic pressure output from the first and second output ports 51A and 51B of the slave cylinder 42 is regulated by the regulator valves 54 and 54. Is supplied to the wheel cylinders 26, 27; 30, 31 through the in valves 56, 56; 58, 58 in the open state, and the four wheels can be braked.

  When the VSA device 23 is operated, the pumps 64 and 64 are driven by the motor 65 with the suction valves 68 and 68 being excited and opened, and the pumps 64 and 64 are sucked from the slave cylinder 42 through the suction valves 68 and 68. The brake fluid pressurized at 64 is supplied to the regulator valves 54 and 54 and the in valves 56 and 56; 58 and 58. Accordingly, the brake fluid pressure in the fluid passages 52, 52 is adjusted by exciting the regulator valves 54, 54 and adjusting the opening, and the in-valves 56, 56; 58, 58 that open the brake fluid pressure are used. By selectively supplying to the wheel cylinders 26, 27; 30, 31, the braking force of the four wheels can be individually controlled even when the driver does not step on the brake pedal 12.

  Therefore, the braking force of the four wheels is individually controlled by the first and second brake actuators 23A and 23B, and the braking force of the inner turning wheel is increased to improve the turning performance, or the braking force of the outer turning wheel is increased to stabilize straight running. Performance can be improved.

  Further, when the driver depresses the brake pedal 12 and detects, for example, that the left rear wheel has a tendency to lock on the low friction coefficient road based on the output of the wheel speed sensor Sg. Exciting one in-valve 58 of the first brake actuator 23A and closing it, and exciting and opening one out-valve 61 allow the brake fluid pressure of the wheel cylinder 26 of the left rear wheel to escape to the reservoir 62. After the pressure is reduced to a predetermined pressure, the out valve 61 is demagnetized and closed to maintain the brake fluid pressure of the wheel cylinder 26 of the left rear wheel. As a result, when the locking tendency of the wheel cylinder 26 of the left rear wheel is resolved, the brake fluid pressure from the first output port 51A of the slave cylinder 42 is opened by demagnetizing the in-valve 58 to open the left rear wheel. The braking force is increased by supplying the wheel cylinder 26 and increasing the pressure to a predetermined pressure.

  When the left rear wheel becomes locked again due to this pressure increase, by repeating the pressure reduction → hold → pressure increase, the ABS (anti-lock) that minimizes the braking distance while suppressing the lock on the left rear wheel is repeated.・ Brake system) can be controlled.

  The ABS control when the left rear wheel wheel cylinder 26 tends to lock has been described above. However, the right rear wheel wheel cylinder 27, the left front wheel wheel cylinder 30, and the right front wheel wheel cylinder 31 tend to lock. The ABS control can be performed in the same manner.

  Next, an operation when the slave cylinder 42 becomes inoperable due to a power failure or the like will be described with reference to FIG.

  When the power supply fails, the first and second master cut valves 32 and 33 made of normally open solenoid valves are automatically opened, and the simulator valve 34 made of normally closed solenoid valves is automatically closed. The in valves 56, 56; 58, 58 and the regulator valves 54, 54 made up of normally-open solenoid valves are automatically opened, and the out valves 60, 60; 61, 61 and the suction valves 68, made up of normally-closed solenoid valves. 68 automatically closes. In this state, the brake fluid pressure generated in the first and second fluid pressure chambers 17 and 19 of the master cylinder 11 is not absorbed by the stroke simulator 35, and the first and second master cut valves 32 and 33, the regulator valve. 54, 54 and the in-valves 56, 56; 58, 58, the wheel cylinders 26, 27; 30, 31 of the disc brake devices 24, 25; 30, 31 of each wheel are actuated to generate a braking force without any trouble. be able to.

  In addition, you may provide separately the member which controls the reverse of 1st, 2nd piston 48A, 48B at the time of failure of the slave cylinder 42. FIG. In this case, it is desirable that the drive resistance is not increased during normal operation.

  Next, the control of the slave cylinder 23 will be described with reference to FIGS.

  As shown in FIG. 5, the stroke of the brake pedal 12 detected by the brake pedal stroke sensor Sd is converted into a target hydraulic pressure to be generated in the slave cylinder 42 by a pedal stroke-target hydraulic pressure map. This pedal stroke-target hydraulic pressure map is calculated by the procedure shown in FIG.

  That is, from the map indicating the relationship between the depression force of the brake pedal 12 and the deceleration to be generated on the vehicle, and the map indicating the relationship between the brake fluid pressure generated by the slave cylinder 42 and the deceleration of the vehicle, the depression force of the brake pedal 12 and A map showing the relationship of the brake fluid pressure to be generated in the slave cylinder 42 is calculated. Subsequently, from this map and a map showing the relationship between the stroke of the brake pedal 12 and the depression force of the brake pedal 12, a map showing the relationship between the stroke of the brake pedal 12 and the target hydraulic pressure to be generated in the slave cylinder 42 (pedal stroke) -Target hydraulic pressure map) is calculated.

  Returning to FIG. 5, the deviation between the target hydraulic pressure to be generated in the slave cylinder 42 calculated from the pedal stroke-target hydraulic pressure map and the actual hydraulic pressure generated by the slave cylinder 42 detected by the second hydraulic pressure sensor Sb is calculated. Then, correction is performed by adding the hydraulic pressure correction amount calculated from this deviation to the target hydraulic pressure. Subsequently, the corrected target hydraulic pressure is applied to a map showing the relationship between the hydraulic pressure generated by the slave cylinder 42 and the stroke of the slave cylinder 42 to calculate the target stroke of the slave cylinder 42. Subsequently, the deviation between the target rotation angle of the motor 44 calculated by multiplying the target stroke of the slave cylinder 42 by a predetermined gain and the actual rotation angle of the motor 44 detected by the motor rotation angle sensor Sf is calculated. By driving the motor 44 with the motor control amount calculated from the above, the slave cylinder 42 generates a brake fluid pressure corresponding to the stroke of the brake pedal 12 detected by the brake pedal stroke sensor Sd.

  By the way, if the motor 44 is dropped from the slave cylinder 42 or the gear train 45 or the ball screw mechanism 46 of the actuator 43 is damaged, the slave cylinder 42 cannot generate brake fluid pressure, but the motor 44 is rotating. There is a possibility that the electronic control unit U does not determine the abnormal state and the backup due to the brake fluid pressure generated by the master cylinder 11 is delayed.

  However, according to the present embodiment, the idling detection means M1 of the electronic control unit U detects the actual stroke of the slave cylinder 42 detected by the slave cylinder stroke sensor Se and the rotation angle of the motor 44 detected by the motor rotation angle sensor Sf over time. The idling of the motor 44 is detected based on the motor rotational speed obtained by differentiation.

As shown in FIG. 7, the idling detection means M1 stores in advance a map showing the relationship between the slave cylinder stroke and the motor rotation speed (see thick solid line). As is apparent from this map, when the slave cylinder stroke is small, the motor rotational speed is high, and the motor rotational speed is set to decrease as the slave cylinder stroke increases. The electronic control unit U, so that the motor rotational speed obtained by differentiating the motor rotation angle detected by the motor rotational angle sensor Sf time, a value corresponding to the slave cylinder stroke detected by the slave cylinder stroke sensor Se, a motor The rotational speed of 44 is controlled.

  At this time, if the motor 44 idles for some reason, the rotational speed of the motor 44 becomes larger than the value determined by the map. Therefore, by setting a hatched area in the map of FIG. 7 and entering the slave cylinder stroke and the motor rotation speed in this area, the idling of the motor 44 can be detected reliably and promptly.

  When the idling of the motor 44 is detected, the electronic control unit U opens the first and second master cut valves 32, 33, closes the simulator valve 34, closes the in valves 56, 56; 58, 58 and By opening the regulator valves 54, 54, closing the out valves 60, 60; 61, 61 and the suction valves 68, 68 to stop the operation of the slave cylinder 42, and shifting to the backup mode shown in FIG. By switching quickly from braking by the brake fluid pressure generated by the slave cylinder 42 to braking by the brake fluid pressure generated by the master cylinder 11, the driver's uncomfortable feeling can be eliminated.

  Next, a second embodiment of the present invention will be described with reference to FIG.

  The second embodiment is different from the first embodiment only in the function of the idling detection means M1, and the other configuration is the same.

  FIG. 8 is a map showing the relationship between the command voltage Vq of the motor 44 subjected to vector control and the torque current Iq. When the motor 44 is not idling normally, as indicated by the solid line, the torque current Iq increases at a constant increase rate as the command voltage Vq increases, and when the command voltage Vq further increases, the increase rate of the torque current Iq increases. It gradually decreases. On the other hand, when the motor 44 is idling, as shown by the broken line, the torque current Iq increases at a constant rate that is significantly lower than that during normal operation as the instruction voltage Vq increases.

  Therefore, by setting a hatched area in the map of FIG. 8 and entering the command voltage Vq and torque current Iq of the motor 44 in this area, the idling of the motor 44 can be detected reliably and promptly.

However, if one of the first and second systems of the slave cylinder 42 fails to leak, the volume of the failed side of the first and second hydraulic pressure chambers 50A and 50B disappears and the normal side is set to the brake hydraulic pressure. until generates because most load on the motor 44 is not generated, in each of the above techniques is likely to not be discriminated and idling and leakage failure of the motor 44.

However, in the present invention, the slave cylinder stroke detected by the slave cylinder stroke sensor Se waits for reaching the magnitude (for example, 20 mm) at which the brake hydraulic pressure is generated in the normal hydraulic chambers 50A and 50B. By performing idling detection using the map, it is possible to reliably determine whether the slave cylinder 42 has leaked and the motor 44 has idled.

  Next, a third embodiment of the present invention will be described.

  The third embodiment is intended for an electric vehicle using a driving motor as a driving source for driving and a hybrid vehicle including a driving motor other than an engine as a driving source for driving.

  In the first and second embodiments, the idling detection means M1 detects the idling of the motor 44 of the slave cylinder 42 until the first and second master cut valves 32 and 33 are opened. There is a possibility that the deceleration of the vehicle may decrease due to a temporary drop in power. In the present embodiment, the auxiliary braking means of the present invention after the idling detection means M1 detects the idling of the motor 44 of the slave cylinder 42 until the first and second master cut valves 32 and 33 are opened. The regenerative braking force generated by the drive motor that functions as is temporarily increased. As a result, it is possible to compensate for a temporary drop in the braking force with the regenerative braking force of the drive motor and to avoid a decrease in the deceleration of the vehicle.

  The embodiments of the present invention have been described above, but various design changes can be made without departing from the scope of the present invention.

  For example, in the embodiment, the motor rotation angle is detected by time differentiation of the motor rotation angle detected by the motor rotation angle sensor Sf, but the motor rotation speed may be directly detected by the motor rotation speed sensor.

11 Master cylinder 12 Brake pedal 26 Wheel cylinder 27 Wheel cylinder 30 Wheel cylinder 31 Wheel cylinder 32 First master cut valve (master cut valve)
33 Second master cut valve (master cut valve)
35 Stroke simulator 42 Slave cylinder 44 Motor
47 cylinder body
48A first piston
48B second piston
50A 1st hydraulic chamber
50B second hydraulic pressure chamber M1 idling detection means U electronic control unit (control means)

Claims (4)

A master cylinder (11) that generates brake fluid pressure by operating the brake pedal (12);
A stroke simulator (35) for applying a reaction force to the operation of the brake pedal (12);
A plurality of wheel cylinders (26, 27, 30, 31) for braking the wheels;
A master cut valve (32, 33) capable of blocking a liquid path connecting the master cylinder (11) and the wheel cylinder (26, 27, 30, 31);
A slave cylinder (42) disposed between the master cut valve (32, 33) and the wheel cylinder (26, 27, 30, 31) and generating brake fluid pressure in response to an operation of the brake pedal (12); ,
Control means for operating the slave cylinder (42) by closing the master cut valve (32, 33) in a state in which the stroke simulator (35) is enabled when the brake pedal (12) is operated. (U) and equipped with a,
The slave cylinder (42) includes a cylinder main body (47) and first and second pistons (48A, 48B) that are slidably fitted in the cylinder main body (47) and are spring-biased in the return direction. ), A first hydraulic chamber (50A) adjacent to the front surface of the first piston (48A) and communicating with the wheel cylinders (26, 27) of the first system, and a front surface of the second piston (48B). A second hydraulic chamber (50B) communicating with the adjacent second wheel cylinder (30, 31), and a motor (44) for driving the first and second pistons (48A, 48B) forward during rotation. And a brake device for a vehicle that changes the stroke of the slave cylinder (42) by rotating the motor (44) in response to an operation of depressing the brake pedal (12). I,
Further comprising slipping detection means for detecting idling of the motor (44) of the slave cylinder (42) (M1),
In the braking process, the idling detection means (M1) causes the stroke of the slave cylinder (42) to brake when one of the first and second hydraulic chambers (50A, 50B) cannot generate brake hydraulic pressure. when a predetermined stroke or more capable of generating hydraulic pressure, to perform an empty Utateken unloading of the motor (44),
When the idling of the motor (44) is detected, the control means (U) opens the master cut valve (32, 33) and brakes the wheel with the brake hydraulic pressure generated by the master cylinder (11). A brake device for a vehicle, wherein the cylinder (26, 27, 30, 31) is operated.   The idling detection means (M1) detects idling of the motor (44) when the rotation speed of the motor (44) is larger than a reference value set according to the stroke of the slave cylinder (42). The vehicle brake device according to claim 1, wherein   The idling detection means (M1) detects idling of the motor (44) by comparing an instruction voltage value of the motor (44) with a torque current value. Brake device for vehicles.   The vehicular brake according to claim 1, further comprising auxiliary braking means for braking a wheel in place of the slave cylinder (42) until the master cut valve (32, 33) is opened. apparatus.

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